I am trying to setup a secondary fax line. I am using a HP-700 fax machine. The fax machine works perfectly for outgoing faxes but cannot receive. I get an error message "the Number you have reached is temporarily unavailable" when I try calling the number via phone. I think something may be wrong with the actual phone line. There are no baud settings on the fax machine or no place to switch off the ECM feature. Is there anything else I can try without giving up on the whole thing. I would rather not buy a new fax machine because I'm not sure that will even work.

If you are getting a message of "the Number you have reached is temporarily unavailable" when you dial your number then a new fax machine is not going to help you. You need to figure out why dialing your number does not ring through to the second line.